Hepatitis C viraemic and seroprevalence and risk factors for positivity in Northwest Cambodia: a household cross-sectional serosurvey.

BACKGROUND: Despite a dramatic reduction in HCV drug costs and simplified models of care, many countries lack important information on prevalence and risk factors to structure effective HCV services. METHODS: A cross-sectional, multi-stage cluster survey of HCV seroprevalence in adults 18 years and above was conducted, with an oversampling of those 45 years and above. One hundred forty-seven clusters of 25 households were randomly selected in two sets (set 1=24 clusters ≥18; set 2=123 clusters, ≥45). A multi-variable analysis assessed risk factors for sero-positivity among participants ≥45. The study occurred in rural Moung Ruessei Health Operational District, Battambang Province, Western Cambodia. RESULTS: A total of 5098 individuals and 3616 households participated in the survey. The overall seroprevalence was 2.6% (CI95% 2.3-3.0) for those ≥18 years, 5.1% (CI95% 4.6-5.7) for adults ≥ 45 years, and 0.6% (CI95% 0.3-0.9) for adults 18-44. Viraemic prevalence was 1.9% (CI95% 1.6-2.1), 3.6% (CI95% 3.2-4.0), and 0.5% (CI95% 0.2-0.8), respectively. Men had higher prevalence than women: ≥18 years male seroprevalence was 3.0 (CI95% 2.5-3.5) versus 2.3 (CI95% 1.9-2.7) for women. Knowledge of HCV was poor: 64.7% of all respondents and 57.0% of seropositive participants reported never having heard of HCV. Risk factor characteristics for the population ≥45 years included: advancing age (p< 0.001), low education (higher than secondary school OR 0.7 [95% CI 0.6-0.8]), any dental or gum treatment (OR 1.6 [95% CI 1.3-1.8]), historical routine medical care (medical injection after 1990 OR 0.7 [95% CI 0.6-0.9]; surgery after 1990 OR 0.7 [95% CI0.5-0.9]), and historical blood donation or transfusion (blood donation after 1980 OR 0.4 [95% CI 0.2-0.8]); blood transfusion after 1990 OR 0.7 [95% CI 0.4-1.1]). CONCLUSIONS: This study provides the first large-scale general adult population prevalence data on HCV infection in Cambodia. The results confirm the link between high prevalence and age ≥45 years, lower socio-economic status and past routine medical interventions (particularly those received before 1990 and 1980). This survey suggests high HCV prevalence in certain populations in Cambodia and can be used to guide national and local HCV policy discussion.

Field evaluation of GeneXpert® (Cepheid) HCV performance for RNA quantification in a genotype 1 and 6 predominant patient population in Cambodia.

GeneXpert® (Cepheid) is the only WHO prequalified platform for hepatitis C virus (HCV) nucleic acid amplification testing that is suitable for point-of-care use in resource-limited contexts. However, its application is constrained by the lack of evidence on genotype 6 (GT6) HCV. We evaluated its field performance among a patient population in Cambodia predominantly infected with GT6. Between August and September 2017, we tested plasma samples obtained from consenting patients at Médecins Sans Frontières' HCV clinic at Preah Kossamak Hospital for HCV viral load (VL) using GeneXpert® and compared its results to those obtained using COBAS® AmpliPrep/Cobas® TaqMan® HCV Quantitative Test, v2.0 (Roche) at the Institut Pasteur du Cambodge. Among 769 patients, 77% of the seropositive patients (n = 454/590) had detectable and quantifiable VL using Roche and 43% (n = 195/454) were GT6. The sensitivity and specificity of GeneXpert® against Roche were 100% (95% CI 99.2, 100.0) and 98.5% (95% CI 94.8, 99.8). The mean VL difference was -0.01 (95% CI -0.05, 0.02) log10  IU/mL for 454 samples quantifiable on Roche and -0.07 (95% CI -0.12, -0.02) log10  IU/mL for GT6 (n = 195). The limit of agreement (LOA) was -0.76 to 0.73 log10  IU/mL for all GTs and -0.76 to 0.62 log10 IU/mL for GT6. Twenty-nine GeneXpert® results were outside the LOA. Frequency of error and the median turnaround time (TAT) for GeneXpert® were 1% and 0 days (4 days using Roche). We demonstrated that the GeneXpert® HCV assay has good sensitivity, specificity, quantitative agreement, and TAT in a real-world, resource-limited clinical setting among GT6 HCV patients.

Demonstration of the diagnostic agreement of capillary and venous blood samples, using hepatitis-C virus SD Bioline© rapid test: A clinic-based study.

BACKGROUND: Simplifying hepatitis C virus (HCV) screening is a key step in achieving the elimination of HCV as a global public health threat by 2030. OBJECTIVES: The objective of this study was to demonstrate the agreement of capillary blood and venipuncture specimens when using SD Bioline© HCV, a low-cost rapid diagnostic test (RDT), prequalified by WHO in 2016 on venous blood samples. STUDY DESIGN: Recruitment was conducted prospectively among adult patients presenting for HCV testing at the Médecins Sans Frontières (MSF) clinic of Preah Kossamak Hospital (Phnom Penh, Cambodia) between October and November 2017. Capillary and venous blood samples were collected from consenting patients and tested with SD Bioline© HCV. Two independent, blinded readers, and in the case of disagreement, a third reader, interpreted the results of each blood sample. Concordance between results was compared using Cohen's Kappa interrater reliability statistic. Discrepant sample pairs were tested with an enzyme immunoassay, the reference standard, at the Institute Pasteur of Cambodia. RESULTS: Among 421 pairs of samples collected, reader disagreement occurred for 0.7% (n = 3) of the participants. Sixty-four percent of capillary and venous blood sample pairs tested positive for HCV, with a Kappa statistic of 0.985 between the two methods. Three participants with discrepant sample pair results tested positive with EIA. CONCLUSIONS: Capillary and venous blood samples were concordant when tested with HCV SD Bioline© in a clinical context. This simplified testing approach is essential to the scale-up of HCV screening and useful in resource-limited settings or among populations for whom venipuncture is problematic.